Device for detecting and correcting defects in the flatness of a product in strip form

ABSTRACT

Device for detecting and correcting defects in the evenness of a product in the form of a strip during treatment, comprising a roller arranged transversally to the travelling direction of the strip and divided into sections capable of movement with respect to one another and position indicators of the various sections being placed outside the rollers, these indicators being formed by hydraulic cylinders, which may be isolated from their supply circuit.

United States Patent [19 Diolot June 18, 1974 DEVICE FOR DETECTING AND CORRECTING DEFECTS IN THE FLATNESS [56] References Cited OF A PRODUCT IN STRIP FORM UNITED STATES PATENTS Inventor: Lucien Diolot Neuiuy France I Harford 8t 3|. 3,581,536 6/1971 Terwilliger 72/9 [73] Asslgneez Soctete Nouvelle Spldem, Pans,

France Primary Examiner-Milton S. Mlehr [22] Filed: Sept 17 1973 Attorney, Agent, or FirmEdwin E. Griegg [21] Appl. No.: 398,076 [57] ABSTRACT Related US. Application Dat Device for detecting and correcting defects in the [63] Continuation of Ser. No. 175,441 Aug. 27. 1971. evenness of a QQ the form of a during abandon treatment, comprising a roller arranged transversally to the travelling direction of the strip and divided into 30 F i Application priority m sections capable of movement with respect to one another andposition indicators of the various sections Aug. 27, 1970 France 70.31357 being placed Outside the rollers, these indicators being 52 us. Cl. 73/159, 72/17 formed by hydrauh? Cylinders which may he isolated 51 Int. Cl. B21d 7/04 from their supply [58] Field of Search 72/8, 9, 12, 17; 73/159 9 Claims, 1 Drawing Figure DEVICE FOR DETECTING AND CORRECTING DEFECTS IN THE ELATNESS OF A PRODUCT IN STRIP FORM whose defects are to be detected and corrected, in the present case the metal strip being rolled. This roller is divided into successive transverse sections which are fast with one another but are nevertheless capable of a certain amount of relative transverse displacement. Since the roller assembly is applied against the metal strip with asubstantialforce, the tension of the latter results ina reaction at each of the sections of the roller, this reaction depending precisely on the temporary tension to which the portion of strip corresponding to the section in question is subjected. The partial tensions corresponding to the various sections may vary relatively to one another and the same applies as regards the transverse positions of the corresponding roller sections, whose position in space is consequently modified. A displacement detector is associated with each of thesections, the indications of this detector reproducing precisely the inequalities which appear between the partial tensions of each of the portions of strip monitored.

In a general way, in known devices of this type, the indicators for the positions of each transverse section of the roller are situated within the roller, in order not to disturb peripheral uniformity.

This arrangement results in a certain number of drawbacks particularly constructional difficulties due to the relatively small diameter of the roller; it is also not easy to arrange the connections of the said indicators, whether these are strain gauges, mechanical detectors or hydraulic jacks, the latter being used in the aforesaid patent application.

Moreover, such devices are necessarily intricate and expensive to maintain.

The device according to the present invention makes itpossible to obviate these various disadvantages.

According to one feature of the invention, the devices for indicating the position of the various transverse sections of the roller are arranged not internally but externally of the latter. This kind of arrangement is applicable whether the roller is subdivided into a cer-- tain number of transverse sections or whether it is simply a case of a roller made in one piece, but having a certain elasticity, which enables it to show slight deformations in dependence on variations in the tension of the strip at different points on the line of contact between strip and roller.

According to a further feature of the invention, means are provided which can be interposed between the roller and the position indicators, these means being intended to facilitate contacts between the indicators which are arranged in fixed positions and, on the other hand, the peripheral surface of the roller, which is constantly rotating.

According to another feature of the invention, the

assembly constituted by the roller, the position indicators and the means interposed between the aforesaid elements is arrangedwithin a frame which is preferably closed and from whichemerges, at its upperportion, the longitudinal zone of the roller which is intended to come into contact with the strip.

As in the case of the known devices, the signals emanating from the indicators are transmitted to appropriate detectors each of which is connected to en element known by itself and on which depends the correction made in the treatment machine, the rolling mill in the present case, this correctionhaving the result of compensating to the desired extent for theexcess or lack of tension manifested in the portion of strip corresponding to the indicator in question.

According to another feature of the invention, the pressure pickups are used at the same time as means for reacting to the pressure acting on the roller owing to the tension of the strip. In fact this tension, which is assumed to'be applied along the line of contact between the strip and the roller, has the result of urging the latter towards the interior of the frame from which it projects; therefore, it is advantageous to direct thereaction force emanating from the position indicators in the opposite sense to the aforenoted pressure, thatis to say in a direction such that the roller is subjected this time toa pressure directed towards the exterior of the frame.

As a safety measure, it is preferable to provideabutments limiting the travel of the reaction elements so that the roller of the device does not go beyond the predetermined position in the sense of its displacement in the direction of the strip.

When, theoretically, equilibrium between the forces present is achieved, the roller is maintained at an invariable level. Therefore, it is possible toallowthe journals of the roller a degree of freedom in the traverse direction relatively to the plane of the strip.

Other advantages and features of the present invention will become apparent from the following description with reference to the accompanying drawing, the description and drawing concerning a" preferred constructional form of the invention, which is given only by way of illustration and is not intended to be limiting.

The single FIGURE shows a general cross section through the device according to the invention.

A roller 1, known by itself, is engaged by a strip product 2 passing in the direction of the arrow f and exerting on the roller 1, along the common contact face 3 between the strip and the roller a certain pressure under the influence of which the roller 1 tends to move into the surrounding housing 4. The roller 1 may be formed of a plurality of axially adjoining sections as shown, for example, in FIG. 3 of the aforementioned patent application.

Two position indicators 5 and 6 formed as hydraulic jacks have, according to the invention, the function, among others, to act as force-producing means intended to compensate for the pressure exerted on the roller by the strip 2. It is noted that, in case the roller 1 is formed of sections as indicated before, with each such section there is associated one pair of hydraulic jacks 5, 6. In the example being considered, the two hydraulic jack indicators 5, 6 bear on a cross member 7 of the housing or frame 4 and constitute transducer means.

In order to provide an abutment or stop at the end of the travel of each of these jacks, its cylinder is shaped accordingly as indicated in the drawing at 5a; the initial pressure prevailing in the jacks thus arranged, before the machine starts, is defined so as to bring about an incident pressure in the .case of the drawing, slightly greater than the dead weight of the roller.

An articulated device which will be described hereinafter is interposed between each pair of jacks 5 and 6 and the roller 1.

The device in question comprises two pivotable arms 8 and 9 articulated on a pivot 10 and each terminating at the opposite end in a wheel 11 and 12 respectively rotating freely about shafts such as 13 and 14.

The jacks 5 and 6, bearing on the cross member 7 of the frame 4, are arranged so as to exert their forces on the arms 8 and 9, the wheels 11 and 12 being then applied against the periphery of the roller 1.

To permit the jacks 5 and 6 to perform their task as pressure pick-ups, it is sufiicient to lock-in the quantity of fluid which each of them contains and then to provide a pressure indicator in the circuit of each jack, this indicator being also arranged so as to be capable of emitting a signal which fluctuates in time and is consequently adapted to follow the variations in the position in space of the section of roller 1 corresponding to the median plane common to the two wheels 11 and 12.

By associating with each component transverse section of the roller an assembly of wheels 11 and 12 and also their accessories, as illustrated in the drawing, a succession of wheels in the direction of the width of strip 2 is obtained.

It should be noted that the pivot 10 may be a sole shaft that extends all along the axis of the main roller 1 and parallel thereto. As for the various shafts 13 and 14 corresponding to the successive wheels 11 and 12, they will be in alignment when the device is in the inoperative state but already under stress. In operation, on the other hand, these various shafts will become slightly offset relatively to one another under the action of the pressure difference resulting from the deformations to which the main roller 1 is subjected.

The outlet conduits 15 and 16 of the jacks 5 and 6 are directly connected in parallel then connected to a pressure indicator 17. Upstream of this indicator there is arranged a shutoff device, a valve 18, for example, whereby the apparatus situated downstream can be completely shut off from the pressure source. Upstream of the shut off device 18, the installation which has just been described is connected to a general supply header 19 into which the hydraulic pressure generator 20 delivers. The general supply header 19 supplies by branch flows all the other assemblies similar to tha illustrated in the drawing and associated with separate, axially adjoining sections of the roller 1. Each of the assemblies can be separated from the header by means of the shutoff device such as the valve 18..

The journal 22 of the roller 1 is capable of moving along substantially vertical slideways 21 (one shown). The device operates as follows.

Considering the transverse section of the roller 1 shown in the drawing, it will be assumed that the corresponding portion of the strip 2 is subjected to an increase in the tension acting on it.

Consequently, the section in question of the roller 1 will be urged downwardly in the drawing, that is to say towards the interior of the frame 4 constituting a housing. This tendency will be transmitted by the wheels 11 and 12 to the respective arms 8 and 9 which will each exert pressure on the respective jacks 5 and 6. Since the associated shutoff valve 18 has been previously closed, the appearance of excess pressures will be noted in the mass of fluid held in the two jacks and their connecting conduits, which excess pressures are immediately detected by the indicator 17 which will also emit a signal of an appropriate value in the direction of the control means, which are assumed to be known. The latter, in turn, act on the elements of the rolling mill which are capable of compensating in the desired sense for the increase in the tension detected by the device according to the invention.

In the reverse case, that is to say when, instead of being subjected to an increase in tension, the portion of strip in question is subjected to a decrease in the tension applied thereto, the final result is also the reverse of the foregoing, the indicator 17 this time indicating a drop in pressure in the jacks 5 and 6, and the correcting signal emitted by this indicator is directed in the opposite sense to the previous signal.

Before starting the apparatus it is advantageous to subject it to pressure. For this purpose, the shutoff valves 18 are opened, which makes it possible to equalize by means of the hydraulic source 20 the pressure prevailing in the installation in general, as described. It is then sufficient to isolate each of the assemblies such as that shown in the drawing, closing the shutoff valves 18.

In a modified constructional form, it would be possible to simply maintain in a fixed situation at one side of the system the arms and the corresponding wheels, for example in the case of the drawing the arm 9 and its wheel 12, in which case the jack 6 would simply be dispensed with, and the jack 5 would then be sufficient by itself for transmitting the necessary compensation indicators.

In another modified form of embodiment, more particularly when the variations in the tension of the strip are slight, the roller 1 can be given an additional degree of freedom in the longitudinal direction. In fact, this roller is capable of being supported solely by the two rows of wheels such as 11 and 12. A certain lateral play in the slideway 21 would consequently increase the sensitivity of the reaction of the roller 1 to variations in tension of the strip, thus also resulting in greater sensitivity in the response of the jacks S and 6.

It will be apparent, that it is possible, without departing from the scope of the invention, to modify some of its arrangements or to replace some of the means described therein by equivalent means.

What is claimed is:

I. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section, and

B. sensor means disposed externally of said roller and associated with each roller section for indicating the radial displacements of each roller section, said sensor means including,

a. contacting means in engagement with the outer periphery of each roller section at locations remote from the area of contact between roller and product, said roller sections exerting a varying force on said contacting means in response to said varying tension, and

b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said transducer means including,

1. hydraulic jack means in engagement with said contacting means for sensing said varying forces transmitted thereto by said contacting means and 2. stationarily held cylinder means receiving said hydraulic jack means.

2. An improvement as defined in claim 1, including an abutment provided in each cylinder means cooperating with the associated hydraulic jack means for determining the end of travel thereof.

3. An improvement as defined in claim 1, including A. hydraulic conduit means associated with and common to each hydraulic jack means and B. a hydraulic pressure source connected to said hydraulic conduit means.

4. An improvement as defined in claim 3, including shutoff means, one associated with each transducer means and disposed in said hydraulic conduit means between said transducer means and said hydraulic pressure source.

5. An improvement as defined in claim 4, including pressure indicating means, one disposed in said hydraulic conduit means between said shutoff means and its associated transducer means, each pressure indicating means emits signals in response to the variations in tension in the associated width portion of said product.

6. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising,

A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section, and

B. sensor means disposed externally of said roller and associated with each roller section for indicating the radial displacements of each roller section, said sensor means including,

a. contacting means in engagement with the outer periphery of each roller section at locations remote from the area of contact between roller and product, said roller sections exerting a varying force on said contacting means in response to said varying tension and b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said contacting means including,

1. swingable arm means contacting said transducer means, 2. stationarily held pivot means securing said arm means at one end thereof, and 3. an idler wheel rotatably secured to the other end of said arm means, said wheel having a rotational axis spaced parallel with the rotational axis of said roller, said wheel being in peripheral contact with said roller. 7. An improvement as defined in claim 6, wherein each arm forming said arm means has a common pivotal axis parallel with the rotational axis of said roller.

8. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed as a single piece roller in contact with an adjacent width portion of said product and being mounted for movement in response to the varying tension in the associated width portion of said product contacting said roller, and

B. sensor means disposed externally of said roller and associated therewith for indicating the radial displacement of said roller, said sensor means including,

a. contacting means in engagement with the outer periphery of said roller at locations remote from the area of contact between roller and product, said roller exerting a varying force on said contacting means in response to said varying tension, and

b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said transducer means including,

1. hydraulic jack means in engagement with said contacting means for sensing said varying forces transmitted thereto by said contacting means and 2. stationarily held cylinder means receiving said hydraulic jack means.

9. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising,

A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section,

B. sensor means disposedexternally of said roller and associated with each roller section for indicating the radial displacement of each roller section,

C. journal means associated with said roller,

7 8 D. slideway means associated with said journal means E. meansifor permitting displacement of said journal for permmmg dlsplacemem of Sald Journal means means in the associated slideway means in a plane in the associated slideway means in a direction substantially normal to the plane of said product, and Substantially Parallel with Said Product 

1. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section, and B. sensor means disposed externally of said roller and associated with each roller section for indicating the radial displacements of each roller section, said sensor means including, a. contacting means in engagement with the outer periphery of each roller section at locations remote from the area of contact between roller and product, said roller sections exerting a varying force on said contacting means in response to said varying tension, and b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said transducer means including,
 1. hydraulic jack means in engagement with said contacting means for sensing said varying forces transmitted thereto by said contacting means and
 2. stationarily held cylinder means receiving said hydraulic jack means.
 2. stationarily held cylinder means receiving said hydraulic jack means.
 2. An improvement as defined in claim 1, including an abutment provided in each cylinder means cooperating with the associated hydraulic jack means for determining the end of travel thereof.
 2. stationarily held pivot means securing said arm means at one end thereof, and
 2. stationarily held cylinder means receiving said hydraulic jack means.
 3. an idler wheel rotatably secured to the other end of said arm means, said wheel having a rotational axis spaced parallel with the rotational axis of said roller, said wheel being in peripheral contact with said roller.
 3. An improvement as defined in claim 1, including A. hydraulic conduit means associated with and common to each hydraulic jack means and B. a hydraulic pressure source cOnnected to said hydraulic conduit means.
 4. An improvement as defined in claim 3, including shutoff means, one associated with each transducer means and disposed in said hydraulic conduit means between said transducer means and said hydraulic pressure source.
 5. An improvement as defined in claim 4, including pressure indicating means, one disposed in said hydraulic conduit means between said shutoff means and its associated transducer means, each pressure indicating means emits signals in response to the variations in tension in the associated width portion of said product.
 6. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising, A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section, and B. sensor means disposed externally of said roller and associated with each roller section for indicating the radial displacements of each roller section, said sensor means including, a. contacting means in engagement with the outer periphery of each roller section at locations remote from the area of contact between roller and product, said roller sections exerting a varying force on said contacting means in response to said varying tension and b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said contacting means including,
 7. An improvement as defined in claim 6, wherein each arm forming said arm means has a common pivotal axis parallel with the rotational axis of said roller.
 8. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip product, the improvement comprising A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed as a single piece roller in contact with an adjacent width portion of said product and being mounted for movement in response to the varying tension in the associated width portion of said product contacting said roller, and B. sensor means disposed externally of said roller and associated therewith for indicating the radial displacement of said roller, said sensor means including, a. contacting means in engagement with the outer periphery of said roller at locations remote from the area of contact between roller and product, said roller exerting a varying force on said contacting means in response to said varying tension, and b. transducer means in engagement with said contacting means for receiving said varying force from said contacting means and transforming said varying force into signals of varying magnitude, said transducer means including,
 9. In a device for detecting and correcting defects in the planeness of a longitudinally traveling strip prOduct, the improvement comprising, A. a freely rotatable roller positioned normal to the traveling direction of said product and being in contact with said product along its width, said roller being formed of a plurality of successive, axially aligned and adjoining sections each being in contact with adjacent width portions of said product, each section of said roller being movable radially independently from the other sections in response to the varying tension in the associated width portion contacting the roller section, B. sensor means disposed externally of said roller and associated with each roller section for indicating the radial displacement of each roller section, C. journal means associated with said roller, D. slideway means associated with said journal means for permitting displacement of said journal means in the associated slideway means in a direction substantially normal to the plane of said product, and E. means for permitting displacement of said journal means in the associated slideway means in a plane substantially parallel with said product. 